varying vec4 diffuse,ambientGlobal, ambient;
varying vec3 normal,lightDir,halfVector;
varying float dist;

void main()
{
	vec3 n,halfV,viewV,ldir;
	float NdotL,NdotHV;
	vec4 color = ambientGlobal;
	float att, spotEffect;
	/* a fragment shader can't write a varying variable, hence we need
	a new variable to store the normalized interpolated normal */
	n = normalize(normal);
	
	/* compute the dot product between normal and normalized lightdir */
	NdotL = max(dot(n,normalize(lightDir)),0.0);
	if (NdotL > 0.0) {

		spotEffect = dot(normalize(gl_LightSource[1].spotDirection),
				normalize(-lightDir));
		if (spotEffect > gl_LightSource[1].spotCosCutoff) {
			spotEffect = pow(spotEffect, gl_LightSource[1].spotExponent);
			att = spotEffect / (gl_LightSource[1].constantAttenuation +
					gl_LightSource[1].linearAttenuation * dist +
					gl_LightSource[1].quadraticAttenuation * dist * dist);

			color += att * (diffuse * NdotL + ambient);

			halfV = normalize(halfVector);
			NdotHV = max(dot(n,halfV),0.0);
			color += att * gl_FrontMaterial.specular *
						gl_LightSource[1].specular *
						pow(NdotHV,gl_FrontMaterial.shininess);
		}
	}
	gl_FragColor = color;
}
